PDA

View Full Version : Flight Director whats it referencing A320


Iakklat
3rd Dec 2004, 16:06
During the acceleration phase from say 250kts econ speed to say 300 odd knots econ speed what does the flight director reference in order of priority,say is it looking at energy first or altitude change when climbing?Or is it looking at both factors,but in what percentage or proportion?
:ok:

strikerA320
3rd Dec 2004, 16:51
Either with "Climb" or "Open Climb" with Speed in "Manage" or "Selected", FD's Referencing will be the energy or speed.

Iakklat
4th Dec 2004, 03:49
Striker i dont think that is entirely correct.The fd has a combination of factors that it is referencing in that phase it is not just looking at attaining the speed,but,it is also looking at the change in ht and is blending these two together at a certain percentage.What that is i would like to know.:=

idg
4th Dec 2004, 05:42
Iakklat

Seem to remember that its 30%/70% but cannot find a reference anywhere at the moment. Will try and find it and post sometime.

Aztec Kid
11th Dec 2004, 19:11
I have a limited number of pages from a document titled, Honeywell A320 Full Standard Symposium, June 1992, and was able to find this:

During acceleration segments the system uses a "60:40 energy ratio (60% acceleration and 40% climb)".

I hope this is what you looking for.

Best regards,
The Kid

And Then
12th Dec 2004, 00:50
Salutations Aztec

I have flown various models and standards of Airbus, and concur with your 6 parts acceleartion, 4 parts delta altitude, energy model.

However, on further referencing, I discovered some old notes that snuck past me some time ago-

Airbus Industrie Briefing Notes Sept 1998 " energy sharing is applied for acceleration ( 70% ) and for altitude ( 30% ) fom ACC ALT up to first climb speed".

Sits comfortably with me reference the 0.1G autopilot pitch authority.

So many models, so much Franglais, hard to maintain currency as an Airbus Nerd!:8

Perhaps the energy difference to do with different engine models?